U.S. patent application number 12/129326 was filed with the patent office on 2008-09-18 for endoscope and hydrophilic cap.
This patent application is currently assigned to OLYMPUS MEDICAL SYSTEMS CORP.. Invention is credited to Atsushi GOTO, Masahiro HAGIHARA, Hiroaki KINOSHITA, Kiyoshi TSUJI, Takao YAMAGUCHI, Hirofumi YAMAMOTO.
Application Number | 20080228035 12/129326 |
Document ID | / |
Family ID | 38091997 |
Filed Date | 2008-09-18 |
United States Patent
Application |
20080228035 |
Kind Code |
A1 |
HAGIHARA; Masahiro ; et
al. |
September 18, 2008 |
ENDOSCOPE AND HYDROPHILIC CAP
Abstract
An endoscope includes: an insertion portion including a distal
end portion, to be inserted into a subject; an observation optical
system disposed in the insertion portion; an optical member
configuring a part of an outer surface of the distal end portion,
through which a photographing light to be incident into the
observation optical system transmits; a first hydrophilic portion
that is film-formed at least on a surface of the optical member; a
second hydrophilic portion that is film-formed on a first surface
of the distal end portion in which the optical member is disposed;
and a third hydrophilic portion that is film-formed on a second
surface separate from the first surface of the distal end
portion.
Inventors: |
HAGIHARA; Masahiro; (Tokyo,
JP) ; YAMAGUCHI; Takao; (Tokyo, JP) ; TSUJI;
Kiyoshi; (Tokyo, JP) ; GOTO; Atsushi; (Tokyo,
JP) ; KINOSHITA; Hiroaki; (Tokyo, JP) ;
YAMAMOTO; Hirofumi; (Tokyo, JP) |
Correspondence
Address: |
SCULLY SCOTT MURPHY & PRESSER, PC
400 GARDEN CITY PLAZA, SUITE 300
GARDEN CITY
NY
11530
US
|
Assignee: |
OLYMPUS MEDICAL SYSTEMS
CORP.
Tokyo
JP
|
Family ID: |
38091997 |
Appl. No.: |
12/129326 |
Filed: |
May 29, 2008 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2006/321272 |
Oct 25, 2006 |
|
|
|
12129326 |
|
|
|
|
Current U.S.
Class: |
600/121 ;
600/176 |
Current CPC
Class: |
G02B 23/2476 20130101;
A61B 1/00096 20130101; A61B 1/00071 20130101; A61B 1/00101
20130101; G02B 23/2423 20130101; A61B 1/127 20130101; G02B 1/11
20130101; G02B 1/10 20130101; A61B 1/0011 20130101 |
Class at
Publication: |
600/121 ;
600/176 |
International
Class: |
A61B 1/00 20060101
A61B001/00; A61B 1/06 20060101 A61B001/06 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 1, 2005 |
JP |
2005-348392 |
Claims
1. An endoscope comprising: an insertion portion including a distal
end portion, to be inserted into a subject; an observation optical
system disposed in the insertion portion; an optical member
configuring a part of an outer surface of the distal end portion,
through which a photographing light to be incident into the
observation optical system transmits; a first hydrophilic portion
that is film-formed at least on a surface of the optical member; a
second hydrophilic portion that is film-formed on a first surface
of the distal end portion in which the optical member is disposed;
and a third hydrophilic portion that is film-formed on a second
surface separate from the first surface of the distal end
portion.
2. The endoscope according to claim 1, wherein the first
hydrophilic portion, the second hydrophilic portion, and the third
hydrophilic portion are hydrophilic films that are continuously
formed.
3. The endoscope according to claim 1, further comprising a fourth
hydrophilic portion that is film-formed on an outer surface of the
insertion portion.
4. The endoscope according to claim 2, further comprising a fourth
hydrophilic portion that is film-formed on an outer surface of the
insertion portion.
5. A hydrophilic cap comprising: a cylindrical body having an
essentially circular ring shape, that is detachably attachable to a
distal end portion of an endoscope; a transparent plate body
disposed on one end of the cylindrical body; and a hydrophilic
portion that is film-formed on a surface of at least the plate
body.
6. The hydrophilic cap according to claim 5, wherein the
hydrophilic portion is film-formed on an outer circumferential
surface of the cylindrical body to be continuous with a surface of
the plate body.
7. An endoscope comprising: an insertion portion including a distal
end portion, to be inserted into a subject; an observation optical
system disposed in the insertion portion; an optical member
configuring a part of an outer surface of the distal end portion,
through which a photographing light to be incident into the
observation optical system transmits; a cylindrical body having an
essentially circular ring shape, that is detachably attachable to
the distal end portion; a transparent plate body disposed on one
end of the cylindrical body; and a hydrophilic portion that is
film-formed on a surface of at least the plate body.
8. The endoscope according to claim 7, wherein the hydrophilic
portion is film-formed on an outer circumferential surface of the
cylindrical body to be continuous with the surface of the plate
body.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation application of
PCT/JP2006/321272 filed on Oct. 25, 2006 and claims benefit of
Japanese Application No. 2005-348392 filed on Dec. 1, 2005, the
entire contents of which are incorporated herein by this
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an endoscope having an
insertion portion including an image pickup portion to be inserted
into a body cavity or an abdominal cavity during diagnosis,
inspection or therapy, and to a hydrophilic cap to be attached to
this endoscope.
[0004] 2. Description of the Related Art
[0005] In recent years, endoscopes have been widely used that can
perform diagnosis, inspection or therapy of organs, biological
tissues, etc., in a body cavity or abdominal cavity. The endoscopes
include, for example: a flexible endoscope including a flexible
insertion portion to be inserted from an anus or oral cavity into a
body cavity such as a large intestine, stomach, etc.; and a rigid
endoscope including a rigid insertion portion to be inserted from
an incised portion into a body for operation in the abdominal
cavity under the endoscope observation.
[0006] These endoscopes include a lens unit to obtain an image of
an organ, etc., and an image pickup device or an image pickup
portion such as a glass fiber-made image guide fiber and a relay
lens. On a distal end surface of the insertion portion of the
endoscope, a cover member with light transparency is provided in
front of the lens unit. A surface of this cover member configures
one outer surface of the distal end surface of the insertion
portion.
[0007] When the insertion portion of the endoscope is inserted into
a body cavity or abdominal cavity, the cover member is in some
cases fogged because of a temperature difference between the
outside air and the inside of the body cavity. Accordingly, to
prevent the fogging of the cover member, as described in, e.g.,
Japanese unexamined patent publication No. 7-275185, a technique is
disclosed to remove fogging by covering the insertion portion with
a sheath having a cleaning nozzle to spray a fluid on a surface of
a cover member subjected to a defogging processing.
[0008] Further, as described in, e.g., Japanese Unexamined Patent
Publication No. 2004-267583, a technique is disclosed to prevent
fogging by forming a thin film containing a photocatalyst on a
surface of a cover member for hydrophilization. This endoscope can
prevent the fogging because even if the surface of the cover member
is adhered with a liquid such as a body fluid in the body cavity or
abdominal cavity, water caused by humidity, and a physiological
saline solution, the liquid becomes a water film that is evenly wet
and spread.
SUMMARY OF THE INVENTION
[0009] An endoscope of the present invention includes an insertion
portion including a distal end portion, to be inserted into a
subject; an observation optical system disposed in the insertion
portion; an optical member configuring a part of an outer surface
of the distal end portion, through which a photographing light to
be incident into the observation optical system transmits; a first
hydrophilic portion that is film-formed at least on a surface of
the optical member; a second hydrophilic portion that is
film-formed on a first surface of the distal end portion in which
the optical member is disposed; and a third hydrophilic portion
that is film-formed on a second surface separate from the first
surface of the distal end portion.
[0010] Further, a hydrophilic cap of the present invention
includes: a cylindrical body having an essentially circular ring
shape, that is detachably attachable to a distal end portion of an
endoscope; a transparent plate body disposed on one end of the
cylindrical body; and a hydrophilic portion that is film-formed on
a surface of at least the plate body.
[0011] According to the present invention described above, there
can be realized an endoscope and a hydrophilic cap attachable to
and detachable from the endoscope that can clearly photograph an
image in a highly humid body cavity even if an operation is
performed for a long period of time with the endoscope and the
hydrophilic left inserted in the body cavity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 relates to a first embodiment, and is a general
configuration view showing a rigid endoscope system.
[0013] FIG. 2 relates to the first embodiment, and is a plan view
showing a distal end surface of a rigid endoscope having a first
hydrophilic portion.
[0014] FIG. 3 relates to the first embodiment, and is a sectional
view of a distal end part of the rigid endoscope shown in FIG.
2.
[0015] FIG. 4 relates to the first embodiment, and is a view to
illustrate definitions of water repellent, unprocessed, and
hydrophilic.
[0016] FIG. 5 relates to the first embodiment, and is a plan view
showing the distal end surface of the rigid endoscope having the
first and a second hydrophilic portions.
[0017] FIG. 6 relates to the first embodiment, and is a sectional
view of a distal end part of the rigid endoscope shown in FIG.
5.
[0018] FIG. 7 relates to the first embodiment, and is a plan view
showing the distal end surface of the rigid endoscope having the
first, second and a third hydrophilic portions.
[0019] FIG. 8 relates to the first embodiment, and is a sectional
view of a distal end part of the rigid endoscope shown in FIG.
7.
[0020] FIG. 9 relates to the first embodiment, and is a perspective
view showing a hydrophilic cap that is attachable to and detachable
from the distal end portion of the rigid endoscope.
[0021] FIG. 10 relates to the first embodiment, and is a sectional
view of the distal end part of the rigid endoscope attached with
the hydrophilic cap.
[0022] FIG. 11 relates to the first embodiment, and is a general
configuration view showing a flexible endoscope system.
[0023] FIG. 12 relates to the first embodiment, and is a plan view
showing a distal end surface of a flexible endoscope having a first
hydrophilic portion.
[0024] FIG. 13 relates to the first embodiment, and is a plan view
showing the distal end surface of the flexible endoscope having the
first and a second hydrophilic portion.
[0025] FIG. 14 relates to the first embodiment, and is a plan view
showing the distal end surface of the flexible endoscope having the
first, second and a third hydrophilic portions.
[0026] FIG. 15 relates to a second embodiment, and is a sectional
view of a distal end part of a rigid endoscope.
[0027] FIG. 16 relates to the second embodiment, and is a sectional
view showing a state of grinding a light guide irradiating surface
of the rigid endoscope of FIG. 15.
[0028] FIG. 17 relates to the second embodiment, and is a sectional
view of a distal end part of a rigid endoscope in a modification
example.
[0029] FIG. 18 relates to the second embodiment, and is a sectional
view of the distal end part of the rigid endoscope.
[0030] FIG. 19 relates to the second embodiment, and is a sectional
view showing a state of grinding a light guide irradiating surface
of the rigid endoscope of FIG. 18.
[0031] FIG. 20 relates to a third embodiment, and is a sectional
view showing a distal end part of a rigid endoscope.
[0032] FIG. 21 relates to the third embodiment, and is a plan view
showing a distal end surface of the rigid endoscope.
[0033] FIG. 22 relates to the third embodiment, and is a plan view
showing a distal end surface of a rigid endoscope shown in a
modification example.
[0034] FIG. 23 relates to the third embodiment, and is a plan view
showing the distal end surface of the rigid endoscope to illustrate
heat conversion means.
[0035] FIG. 24 relates to the third embodiment, and is a plan view
shown in a modification example, showing the distal end surface of
the rigid endoscope to illustrate the heat conversion means.
[0036] FIG. 25 relates to the third embodiment, and is a partial
sectional view showing the distal end part of the rigid endoscope
to illustrate the heat conversion means.
[0037] FIG. 26 relates to the third embodiment, and is a partial
sectional view shown in a modification example, showing the distal
end part of the rigid endoscope to illustrate heat conversion
means.
[0038] FIG. 27 relates to the third embodiment, and is a view to
illustrate a minute uneven structure having an antireflection
effect.
[0039] FIG. 28 relates to the third embodiment, and is a
perspective view showing the distal end part of the flexible
endoscope.
[0040] FIG. 29 relates to the third embodiment, and is a
perspective view of the distal end part of the rigid endoscope
showing an exemplary measure to prevent flare caused by
illumination light.
[0041] FIG. 30 relates to the third embodiment, and is a sectional
view of the distal end part of the rigid endoscope of FIG. 29.
[0042] FIG. 31 relates to the third embodiment, and is a partial
sectional view of the distal end part of the rigid endoscope
showing a modification example of the measure to prevent flare
caused by illumination light.
[0043] FIG. 32 relates to the third embodiment, and is a partial
sectional view of the distal end part of the rigid endoscope
showing a modification example of the measure to prevent flare
caused by illumination light.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0044] Referring to the drawings, embodiments according to an
endoscope of the present invention are described below.
First Embodiment
[0045] First, a first embodiment of the present invention is
described.
[0046] FIGS. 1 to 14 relate to the first embodiment. FIG. 1 is a
general configuration view showing a rigid endoscope system. FIG. 2
is a plan view showing a distal end surface of a rigid endoscope
having a first hydrophilic portion. FIG. 3 is a sectional view of a
distal end part of the rigid endoscope shown in FIG. 2. FIG. 4 is a
view to illustrate definitions of water repellent, unprocessed, and
hydrophilic. FIG. 5 is a plan view showing the distal end surface
of the rigid endoscope having the first and a second hydrophilic
portions. FIG. 6 is a sectional view of a distal end part of the
rigid endoscope shown in FIG. 5. FIG. 7 is a plan view showing the
distal end surface of the rigid endoscope having the first, second
and a third hydrophilic portions. FIG. 8 is a sectional view of a
distal end part of the rigid endoscope shown in FIG. 7. FIG. 9 is a
perspective view showing a hydrophilic cap that is attachable to
and detachable from the distal end portion of the rigid endoscope.
FIG. 10 is a sectional view of the distal end part of the rigid
endoscope attached with the hydrophilic cap. FIG. 11 is a general
configuration view showing a flexible endoscope system. FIG. 12 is
a plan view showing a distal end surface of a flexible endoscope
having a first hydrophilic portion. FIG. 13 is a plan view showing
the distal end surface of the flexible endoscope having the first
and a second hydrophilic portions. FIG. 14 is a plan view showing
the distal end surface of the flexible endoscope having the first,
second and a third hydrophilic portions.
[0047] As shown in FIG. 1, a rigid endoscope system 100 includes a
rigid endoscope 1, a monitor 6 for displaying an endoscope image, a
control unit (hereinafter abbreviated as CCU) 7 which is connected
to the monitor 6 and outputs an image-processed endoscope image,
and a light source apparatus 10 for outputting illumination light
to the rigid endoscope 1.
[0048] The rigid endoscope 1 includes a distal end portion 2, a
rigid insertion portion 3 which is provided in a linked manner to a
proximal end of the distal end portion 2, and a grasping portion 4
which is provided in a linked manner to a proximal end of the
insertion portion 3. The grasping portion 4 includes a light guide
connector portion 5. The light guide connector portion 5 is
connected with a connector portion 12 of a light guide cable 11
connected to the light source apparatus 10. A proximal end of the
grasping portion 4 is connected with a camera head 9 incorporating
an image pickup device unit comprised of a CCD or CMOS. The camera
head 9 is connected to a CCU 7 with an electric cable 8.
[0049] As shown in FIGS. 2 and 3, the rigid endoscope 1 includes,
on a distal end surface thereof: a glass surface portion 15a of a
cover glass 15 which is an optical member having light
transparency; a distal end surface 16a of an optical member holding
tube 16 for holding the cover glass 15 at a distal end position;
and an irradiating surface 17a of a light guide 17 in a region
formed between the distal end surface 16a of the optical member
holding tube 16 and a distal end surface 2a of the distal end
portion 2.
[0050] Note that the center axis of the optical member holding tube
16 for holding the cover glass 15 is arranged at a position
decentered with respect to the center axis of the distal end
portion 2 and the insertion portion 3.
[0051] Inside the optical member holding tube 16, there is disposed
a lens holding tube 19 for holding an optical (object) lens group
18 including a plurality of lenses configuring an observation
optical system, and a group of a plurality of relay lenses not
shown and introducing image pickup light condensed by the optical
lens group 18 to an image pickup device in the camera head 9.
[0052] The image pickup device unit in the camera head 9 converts
the condensed image pickup light to an image signal. This image
signal is then transmitted to the CCU 7 by the electric cable 8
connected to the camera head 9 shown in FIG. 1.
[0053] Note that the rigid endoscope 1 is not limited to one having
a relay lens group in the insertion portion 3, but may be one
including the image pickup device unit in the insertion portion 3.
In such type of the rigid endoscope 1, for example, a communication
cable extends from the image pickup unit in the insertion portion
3, to be inserted through the insertion portion 3 and extendedly
provided up to the proximal end of the grasping portion 4. The
communication cable is electrically connected to an electric cable
by a connector connected to the grasping portion 4. This electric
cable is connected to the CCU 7, so that the condensed image pickup
light from the image pickup device unit is transmitted to the CCU 7
by an image signal.
[0054] The light guide 17 is subjected to a grind processing such
that the irradiating surface 17a of the introduced illumination
light is positioned in the same plane as the distal end surface of
the distal end portion 2, and inserted in through the insertion
portion 3 up to the light guide connector portion 5 of the grasping
portion 4 shown in FIG. 1. The light guide 17 is further connected
to the connector portion 12 of the light guide cable 11 to
introduce the illumination light from the light source apparatus
10.
[0055] The glass surface portion 15a of the cover glass 15 and the
distal end surface 16a of the optical member holding tube 16 of the
present embodiment are subjected to a hydrophilic processing by,
for example, a transparent thin-film photocatalyst such as titanium
oxide, so that a first hydrophilic portion 20 is film-formed in the
regions of the glass surface portion 15a and the distal end surface
16a.
[0056] Here, using FIG. 4, hydrophicility of the present embodiment
is defined below.
[0057] As shown in FIG. 4, in general, a contact angle .theta. with
a member surface adhered with a liquid 25 having a water drop
shape, which is greater than 80 degrees (.theta.>80 degrees),
e.g., because the member surface is processed with an ion wax,
Teflon (a registered trademark), etc., is regarded as water
repellent; the contact angle .theta. which is approximately 50
degrees (.theta./50 degrees) as unprocessed; and the contact angle
.theta. which is smaller than 20 degrees (.theta.>20 degrees)
because of the below-described processing, as hydrophilic.
[0058] The rigid endoscope 1 of the present embodiment includes the
first hydrophilic portion 20 having the glass surface portion 15a
of the cover glass 15 and the distal end surface 16a of the optical
member holding tube 16 subjected to the defogging processing of the
hydrophilic processing. Thus, the rigid endoscope 1 is configured
such that, even if the distal end portion 2 is adhered with the
liquid 25 such as a body fluid, a water drop resulting from steam,
a physiological saline solution, etc., the liquid adhering on the
cover glass 15 imposes no adverse effect on the image pickup light
condensed by the image pickup device unit 18a via the cover glass
15 and the optical lens group 18 to obtain an endoscope image.
[0059] The contact angle .theta. preferable for the first
hydrophilic portion 20 is not greater than 10 degrees
(.theta..ltoreq.10 degrees) of the above-defined hydrophicility.
More preferably, the first hydrophilic portion 20 is in a super
hydrophilic state such that a water drop adhering on the surfaces
of the glass surface portion 15a and the distal end surface 16a has
a contact angle .theta. not greater than 5 degrees
(.theta..ltoreq.5 degrees). Moreover, the first hydrophilic portion
20 has an enough tolerance for autoclave processing which is a high
temperature-high pressure steam sterilization processing performed
in cleaning sterilization of the rigid endoscope 1.
[0060] Returning to FIG. 3, the rigid endoscope 1 constructed as
above prevents fogging by means of the first hydrophilic portion
20, and causes a fluid 26 adhering on the distal end surface of the
distal end portion 2 to turn into a conformed state without
becoming a water drop on the glass surface portion 15a and the
distal end surface 16a. The fluid 26 becomes a water drop swelled
by surface tension on the distal end surface 2a of the distal end
portion 2 not subjected to hydrophilic processing. Note that FIG. 3
shows a state where a bigger water drop 26a is produced on the
distal end surface 2a on a lower part side of the distal end
portion 2 by gravity, assuming that up/down direction as viewed
toward the paper surface is identical with the vertical up/down
direction.
[0061] That is, the rigid endoscope 1 of the present embodiment can
prevent fogging by hydrophilic processing on the distal end surface
16a and the glass surface portion 15a, and especially prevent
production of water drops by fluids such as body fluid, steam and
physiological saline solution in the abdominal cavity, on the glass
surface portion 15a. Therefore, no water drops are produced in the
light path of the image pickup light incident into the image pickup
device unit 18a via the optical lens group 18 from the cover glass
15. Accordingly, the rigid endoscope 1 can eliminate a bad
influence on the image captured of the inside of the abdominal
cavity by distortion due to fog and water drops, etc., thus
obtaining a clear endoscope image.
[0062] The above-mentioned effect can be achieved more surely by
performing the hydrophilic film-forming processing on the entire
area of the distal end surface and a circumferential side surface
of the distal end portion 2 of the rigid endoscope 1 as described
below.
[0063] Specifically, as shown in FIGS. 5 and 6, the rigid endoscope
1 includes, in addition to the above-mentioned first hydrophilic
portion 20, a second hydrophilic portion 21 which is film-formed,
including the irradiating surface 17a of the light guide 17 and the
circular ring-shaped distal end surface 2a of the distal end
portion 2 that are subjected to a defogging processing with a
hydrophilic film.
[0064] The second hydrophilic portion 21 is a hydrophilic film
continuous with the first hydrophilic portion 20 at a boundary
portion between the distal end surface 16a of the optical member
holding tube 16 and the irradiating surface of the light guide 17.
The second hydrophilic portion also has an enough tolerance for the
autoclave processing as the first hydrophilic portion 20, and is a
hydrophilic film that is subjected to a super hydrophilic
processing such that a contact angle of a fluid 26 on the
irradiating surface 17a and the distal end surface 2a that are
super hydrophilic is not greater than 5 degrees (.theta..ltoreq.5
degrees).
[0065] Thus, by the rigid endoscope 1 having the second hydrophilic
portion 21 film-formed, the fluid 26 adhering on the distal end
surface of the distal end portion 2, including the glass surface
portion 15a, the distal end surface 16a, the irradiating surface
17a, and the distal end surface 2a, turns into a conformed state,
without becoming a water drop, as shown in FIG. 6. On the
circumferential side surface of the distal end portion 2 not
subjected to hydrophilic processing, the fluid 26 becomes a water
drop swelled by surface tension. Here, FIG. 6 shows a state where
the water drop 26a is produced on the circumferential side surface
of the distal end portion 2 by gravity, also assuming that up/down
direction as viewed toward the paper surface is identical with the
vertical up/down direction.
[0066] That is, by providing the second hydrophilic portion 21 to
the rigid endoscope 1 that a large view angle such as, e.g., 170
degrees is set, it is prevented that water drops are produced on
the entirety of the distal end surface of the distal end portion 2
and enter the view angle, which enables obtaining a good endoscope
image.
[0067] Note that, to prevent fogging and water drops from being
produced in the light path of the image pickup light incident from
the cover glass 15, the rigid endoscope 1 having the second
hydrophilic portion 21 that is film-formed as above may be
configured such that the first hydrophilic portion 20 is subjected
to the super hydrophilic processing and the second hydrophilic
portion 21 has a hydrophilic characteristic with a contact angle
.theta. not greater than 20 degrees (.theta.<20 degrees) which
is sufficient to prevent general production of water drops, as
mentioned above.
[0068] Furthermore, as shown in FIGS. 7 and 8, also on a
circumferential side surface of the distal end portion 2 of the
rigid endoscope 1, a third hydrophilic portion 22 is film-formed
that is subjected to the defogging processing with a hydrophilic
film. The third hydrophilic portion has an enough tolerance for the
autoclave processing as the first and second hydrophilic portions
20, 21. The third hydrophilic portion 22 is film-formed on the
distal end portion 2 to be a hydrophilic film continuous with the
second hydrophilic portion 21. In other words, the first to third
hydrophilic portions 20 to 22 are here film-formed over the
entirety of the distal end portion 2 to be continuous without a
gap.
[0069] The third hydrophilic portion 23 may be a hydrophilic film
subjected to a super hydrophilic processing such that the contact
angle of the fluid 26 on the irradiating surface 17a and the distal
end surface 2a that are super hydrophilic is not greater than 5
degrees (.theta..ltoreq.5 degrees). Nonetheless, it suffices to
form a film on the circumferential side surface of the distal end
portion 2 such that, for example, the contact angle .theta. becomes
not greater than 30 degrees, instead of the contact angle .theta.
not greater than 20 degrees (.theta.<20 degrees) defined as
hydrophilic above.
[0070] That is, for the rigid endoscope 1 to prevent production of
fogging and water drops to obtain a clear endoscope image, the
smaller the contact angle .theta. of the fluid 26 on the glass
surface portion 15a and on the distal end surface 16a of the first
hydrophilic portion 20, the more preferable. On the other hand, the
rigid endoscope 1 does not need much of the effect to prevent
production of fogging and water drops on the circumferential side
surface of the distal end portion 2. Therefore, the contact angle
.theta. of the fluid 26 on the circumferential side surface of the
distal end portion 2 where the third hydrophilic portion 22 is
film-formed may be set to be somewhat large.
[0071] Here, the third hydrophilic portion 22 is film-formed on the
entirety of the outer circumference portion of the distal end
portion 2. Yet, a length L in the axial direction of a range of the
outer circumferential surface of the distal end portion 2 where the
third hydrophilic portion 22 is film-formed may be about 3 cm from
the distal end surface 2a toward a proximal end side.
[0072] Moreover, not only on the distal end portion 2 of the rigid
endoscope 1, but also on an outer surface of the insertion portion
3, a fourth hydrophilic film may be formed that is similar to each
of the hydrophilic portions 20 to 22. That is, the rigid endoscope
1 has the hydrophilic films formed both on the distal end portion 2
and the insertion portion 3. Thus, a fluid coming into contact with
the outer circumferential surface evenly spreads to improve
insertability into the abdominal cavity.
[0073] Note that each of the above-mentioned effects can be also
achieved by using a hydrophilic cap 30 which is a hydrophilic cap
subjected to the defogging processing with a hydrophilic film and
attachable to/detachable from the distal end portion 2 of the rigid
endoscope 1, as shown in FIGS. 9 and 10. To describe in detail, the
hydrophilic cap 30 includes a cylindrical body 31 with an
essentially circular ring shape having a length that can cover the
entirety of the outer circumference portion of the distal end
portion 2 having elasticity, and a plate member 32 that is
transparent and having a disc shape at a distal end of the
cylindrical body 31.
[0074] The hydrophilic cap 30 has the defogging processing with a
hydrophilic film performed at least on distal end surfaces of the
hydrophilic cap 30, i.e., a surface portion 32a of the plate member
32 and a distal end surface 31a of the cylindrical body 31. In the
present embodiment, a circumferential side surface of the
cylindrical body 31 is also subjected to the defogging processing
with a hydrophilic film. The hydrophilic cap 30 is prevented from
falling off from the distal end portion 2 when attached on the
distal end portion 2, by elastic deformation of the cylindrical
body 31. Note that screw grooves may be formed on the outer
circumferential surface of the distal end portion 2 and on an inner
circumferential surface of the cylindrical body 31 of the
hydrophilic cap 30 to enable the hydrophilic cap 30 to be
detachably attached to the distal end portion 2.
[0075] The hydrophilic cap 30 configured as above prevents the
fluid 26 on the outer surface subjected to the hydrophilic
processing from becoming water drops, and turns the water drops
into a conformed state on the outer surface, as each of the
hydrophilic portions 20 to 22. In other words, the hydrophilic cap
30 has a hydrophilic film same as the above-mentioned first
hydrophilic portion 20 formed on the surface portion 32a of the
plate member 32 and the distal end surface 31a of the cylindrical
body 31, and also has a hydrophilic film same as the
above-mentioned third hydrophilic portion 22 continuously formed on
the outer circumference portion of the cylindrical body 31.
[0076] Thus, the rigid endoscope 1 can constantly obtain a clear
endoscope image by simply changing the hydrophilic cap 30 as the
hydrophilic effect deteriorates.
[0077] Next, hydrophilic processing to form the first to third
hydrophilic portions 20 to 22 is described.
[0078] Each of the hydrophilic portions 20 to 22 of the present
embodiment is subjected to the hydrophilic processing by
film-forming, by the sputtering method, a film of a photocatalyst
such as, e.g., titanium oxide on each of the glass surface portion
15a of the cover glass 15, the distal end surface 16a of the
optical member holding tube 16, the irradiating surface 17a of the
light guide 17, and the distal end surface 2a and the outer
circumferential surface of the distal end portion 2. The outer
surface of the hydrophilic cap 30 is also processed in a similar
manner. So as not to obstruct incidence of the photographing light,
a transparent thin-film photocatalyst is used for at least the
glass surface portion 15a of the cover glass 15 where the first
hydrophilic portion 20 is film-formed.
[0079] Note that each of the hydrophilic portions 20 to 22 is not
to be limitatively subjected to the above-mentioned hydrophilic
processing of forming a transparent thin-film photocatalyst such as
of the titanium oxide by the sputtering method, but may be
subjected to a film-forming processing by a gas-phase method such
as the sputtering method and the evaporation methods, liquid-phase
methods such as dipping coating and spin coating, a method of
applying a medicament that serves as the basis of the hydrophilic
film with a cloth, absorbent cotton, etc., so as to form, e.g., a
thin film of various coating agents having light transparency to
subject each of the above-mentioned surfaces to a hydrophilic
processing.
[0080] Furthermore, the above-mentioned surfaces may be processed
with hydrophilic films to serve as the first to third hydrophilic
portions 20 to 22 by forming a petaloid alumina film having a
minute uneven surface with surface roughness of, e.g., Rz=50 nm-130
nm by the Sol-Gel method.
[0081] Medicaments to serve as the hydrophilic film include a
surfactant for defogging. By applying this surfactant, each of the
hydrophilic portions 20 to 22 is film-formed. Some of the
surfactants for defogging form a hydrophilic film, main ingredients
of which are, e.g., liquid or solid cationic surfactant, anionic
surfactant, non-ionic surfactant, ampho-ionic surfactant, etc.
[0082] Examples of cationic surfactant include alkyl trimethyl
ammonium salt, dialkyl dimethyl ammonium chloride, alkyl pyridinium
chloride, etc. Examples of anionic surfactant include fat acid
salt, alpha.-sulfo-fatty acid ester salt, alkylsulfuric acid
triethanolamine, etc. Examples of non-ionic surfactant include
fatty acid diethanolamides, polyoxyethylene alkyl ether,
polyoxyethylene alkyl phenyl ether, etc. Examples of ampho-ionic
surfactant include alkyl carboxy betaine, etc. Note that these
surfactants are not limited to the above-listed components, and are
sufficed to have biocompatibility. Furthermore, each of the
above-mentioned surfactants for developing the hydrophilic
characteristic may contain an additive such as, e.g., alcohol,
glycerol to facilitate application on the glass surface portion 15a
and the distal end surface 16a and to even the hydrophilic film of
the surfactant.
[0083] Note that, in assembling the rigid endoscope 1, members
thereof may be separately subjected to the hydrophilic film-forming
processing to be thereafter assembled together so as to film-form
the first to third hydrophilic portions 20 to 22. Alternatively,
the members may be assembled in advance to have thereon the first
to third hydrophilic portions 20 to 22 film-formed. The latter way
of assembling can surely form a hydrophilic film also at a border
part between the members, thereby allowing more surely improving
the hydrophilic effect, obtaining high effects of defogging and
preventing water drop production.
[0084] Incidentally, when film-forming each of the hydrophilic
portions 20 to 22, the above-mentioned gas-phase method such as the
sputtering method or the evaporation method can form a hydrophilic
film with constant quality and good reproducibility, once a
film-forming condition is determined. The gas-phase method can form
a film over a comparatively wide range, permitting continuously and
jointlessly forming a hydrophilic film at the border portions of
the members, which enables obtaining high effects of defogging and
preventing water drop production.
[0085] The liquid-phase method such as dipping coating and spin
coating can form a hydrophilic film without requiring expensive
equipment, as compared to the above-mentioned gas-phase method.
Moreover, the liquid-phase method can comparatively easily adjust
thickness and quality of the hydrophilic film. For this reason, the
liquid-phase method has an advantage of enabling to ensure the
quality of the hydrophilic film, minimizing production cost.
[0086] The method of forming a hydrophilic film by applying
surfactant with a cloth or absorbent cotton can be significantly
inexpensive compared to the gas-phase method and the liquid-phase
method and allows the user to freely conduct the application, which
leads to an advantage of providing good usability.
[0087] In each of the above-mentioned methods of forming a
hydrophilic film, for example, each of the first to third
hydrophilic portions 20 to 22 can be film-formed at the same time
after assembling the members of the rigid endoscope 1, thus
allowing forming a film continuously and jointlessly at each of the
border parts of the first to third hydrophilic portions 20 to 22.
Accordingly, the rigid endoscope 1 easily have a water screen
spread on each of the hydrophilic portions 20 to 22 even in a
comparatively high humidity, leading to superior configuration for
the effects of defogging and preventing water drop production,
which enables obtaining a better endoscope image.
[0088] In the case of separately film-forming the first to third
hydrophilic portions 20 to 22 on the members before assembling the
rigid endoscope 1, on the first hydrophilic portion 20 can be
formed a high performance hydrophilic film by the gas-phase method
such as the sputtering method and the evaporation method or by the
liquid-phase method such as dipping coating and spin coating, while
on the second and third hydrophilic portions 21, 22 can be formed a
film inexpensively by the above-mentioned liquid-phase method or a
method using a surfactant. That is, on the first hydrophilic
portion 20 having a direct influence on the photographing light,
there is formed a hydrophilic film with high hydrophilic
characteristic such as super hydrophilic characteristic. On the
second and third hydrophilic portions 21, 22 having less direct
influence on the photographing light, a hydrophilic film with
somewhat lower hydrophilic characteristic is formed. Accordingly,
separate use of the film characteristics is enabled.
[0089] Furthermore, the above-mentioned method does not require
large equipment to perform the gas-phase method such as the
sputtering method and the evaporation method which is adapted to
the size of the rigid endoscope 1 assembled, but permits a normal
sputtering apparatus or evaporation apparatus to form a film on the
cover glass 15 and the optical member holding tube 16, serving as
respective members of the glass surface portion 11a and the distal
end surface 16a, on which the first hydrophilic portion 20 is
film-formed.
[0090] Incidentally, the above-mentioned present embodiment, which
refers to the rigid endoscope 1 having the hydrophilic portions 20
to 22 which is to be inserted in the abdominal cavity, can also be
applied to a flexible endoscope to be inserted into a body cavity
such as the large intestine.
[0091] Referring here to FIGS. 11 to 14, a flexible endoscope
system 200 including a flexible endoscope 40 is briefly
described.
[0092] As shown in FIG. 11, the flexible endoscope system 200
includes the flexible endoscope 40, and the monitor 6, the CCU 7,
and the light source apparatus 10 that are mentioned above.
[0093] The flexible endoscope 40 includes: an insertion portion 44
to be inserted in the body cavity, comprised of a distal end
portion 41, a bending portion 42, and a flexible tube portion 43;
and an operation portion 45 provided in a linked manner to a
proximal end of the insertion portion 44. From the operation
portion 45 extends a universal cord 45a having a connector portion
45b to be connected to the light source apparatus 10.
[0094] As shown in FIG. 12, on a distal end surface 41a of the
distal end portion 41 of the flexible endoscope 40, there are
disposed: an observation window 51 as an optical member through
which photographing light transmits to internal observation means
not shown such as CCD or CMOS; two illumination windows 52, 53 to
irradiate illumination light; an aperture portion of a treatment
instrument channel 54 configuring an endoscope conduit; and a
nozzle 55 to spray a fluid on the observation window 51.
[0095] As shown in FIG. 12, the flexible endoscope 40 of the
present embodiment has a first hydrophilic portion 47 film-formed
on the observation window 51 on the distal end surface 41a and on a
periphery portion 51a of the observation window 51, as the
above-mentioned rigid endoscope 1. The first hydrophilic portion 47
of the flexible endoscope 40 is equivalent to the first hydrophilic
portion 20 of the rigid endoscope 1 shown in FIGS. 2 and 3, and
achieves the same effect.
[0096] The flexible endoscope 40 may further include, in addition
to the first hydrophilic portion 47, a second hydrophilic portion
48 that is film-formed on the entire area of the distal end surface
41a as shown in FIG. 13. The first hydrophilic portion 47 and the
second hydrophilic portion 48 of the flexible endoscope 40 are
equivalent to the first hydrophilic portion 20 and the second
hydrophilic portion 21 of the rigid endoscope 1 shown in FIGS. 5
and 6, and achieve the same effect.
[0097] The flexible endoscope 40 may furthermore include, in
addition to the first and second hydrophilic portions 47, 48, a
third hydrophilic portion 49 that is film-formed on an outer
circumferential surface of the distal end portion 41 as shown in
FIG. 14. The first to third hydrophilic portions 47, 48, 49 of the
flexible endoscope 40 are equivalent to the first to third
hydrophilic portions 20, 21, 22 of the rigid endoscope 1 shown in
FIGS. 7 and 8, and achieve the same effect.
Second Embodiment
[0098] Next, a second embodiment of the present invention is
described.
[0099] FIGS. 15 to 19 relate to the second embodiment. FIG. 15 is a
sectional view of a distal end part of a rigid endoscope. FIG. 16
is a sectional view showing a state of grinding a light guide
irradiating surface of the rigid endoscope of FIG. 15. FIG. 17 is a
sectional view of a distal end part of a rigid endoscope in a
modification example. FIG. 18 is a sectional view of the distal end
part of the rigid endoscope. FIG. 19 is a sectional view showing a
state of grinding a light guide irradiating surface of the rigid
endoscope of FIG. 18.
[0100] Note that, in the description of the present embodiment, the
same components as in the first embodiment use the same symbols,
and descriptions thereof are omitted.
[0101] Incidentally, production of the general rigid endoscope 1
includes a grind processing to grind and surface-trim the light
guide 17 protruded from the distal end surface of the distal end
portion 2 and solder or wax used as fixing means to install the
cover glass 15 to the optical member holding tube 16.
[0102] The light guide 17, which is configured of a fibrous fiber
member, is ground to form the irradiating surface 17a on the distal
end surface of the distal end portion 2.
[0103] On the other hand, a fixing solder or wax is used especially
when installing the cover glass 15 to the optical member holding
tube 16. The solder or wax is for air-tightly/liquid-tightly
maintaining the inside of the insertion portion 3, where the
observation means such as the optical lens group 18 and the relay
lenses are disposed, with respect to the outside, and for ensuring
resistibility to disinfection and sterilization. The soldering or
waxing processes are manually performed. Because the solder or wax
excludes a wipe-off process which is allowed for adhesive, it is
necessary to grind the part of the solder or wax protruded from the
distal end surface.
[0104] In view of the above, the present embodiment is configured
as described below to prevent especially the first hydrophilic
portion 20 that is film-formed on the cover glass 15 from being
exfoliated by the grinding process. Note that the present
embodiment is made valid if the grinding process is performed after
the cover glass 15, on which a hydrophilic portion 23 which is a
hydrophilic film as a defogging coating is film-formed, is
installed in advance to the optical member holding tube 16.
[0105] To describe in detail, as shown in FIG. 15, the rigid
endoscope 1 of the present embodiment has the glass surface portion
11a of the cover glass 15 fixed shifted rearward by about 0.1 mm to
0.5 mm from the distal end surface 16a of the optical member
holding tube 16 disposed in the distal end portion 2. Note that the
optical member holding tube 16 may have a hydrophilic film formed
also on an inner circumferential surface 16b that extends from a
distal end surface 16a of the optical member holding tube 16 to the
glass surface portion 15a of the cover glass 15.
[0106] Such configuration enables grounding the distal end surface
of the distal end portion 2 of the rigid endoscope 1 without the
hydrophilic portion 23 of the glass surface portion 15a of the
cover glass 15 being exfoliated by an grinding tool 60, as shown in
FIG. 16. As a result, the hydrophilic portion 23 can maintain an
effective hydrophilic characteristic.
[0107] Note that, as shown in FIG. 17, the cover glass 15 may have
a concave portion 15b including the glass surface portion 15a
formed therein, and a hydrophilic portion 23a of a hydrophilic film
as a defogging coating may be film-formed on a concave surface of
the concave portion 15b. In other words, the cover glass 15 is
configured to prevent the concave surface of the concave portion
15b from being ground, and the hydrophilic portion 23a exfoliated,
during a grinding process.
[0108] Moreover, as shown in FIG. 18, the cover glass 15, on which
the hydrophilic portion 24 of the hydrophilic film as a defogging
coating is film-formed, may be disposed to the optical member
holding tube 16 so as to be convex on the distal end surface of the
rigid endoscope 1. Such configuration of the rigid endoscope 1
enables grinding, while trimming, especially the irradiating
surface 17a of the light guide 17 without exfoliating the
hydrophilic portion 24 of the cover glass 15 by a grinding tool 61
with a concave portion 61a formed therein, as shown in FIG. 19.
[0109] Note that the grinding tool 60 is configured to be
cocentered with the cover glass 15 to rotate to grind the same,
with the center of the concave portion 61a agreeing with the center
of the cover glass 15.
Third Embodiment
[0110] Next, a third embodiment of the present invention is
described.
[0111] FIGS. 20 to 32 relate to a third embodiment. FIG. 20 is a
sectional view showing a distal end part of a rigid endoscope. FIG.
21 is a plan view showing a distal end surface of the rigid
endoscope. FIG. 22 is a plan view showing a distal end surface of a
rigid endoscope shown in a modification example. FIG. 23 is a plan
view showing the distal end surface of the rigid endoscope to
illustrate heat conversion means. FIG. 24 is a plan view shown in a
modification example, showing the distal end surface of the rigid
endoscope to illustrate the heat conversion means. FIG. 25 is a
partial sectional view showing the distal end part of the rigid
endoscope to illustrate the heat conversion means. FIG. 26 is a
partial sectional view shown in a modification example, showing the
distal end part of the rigid endoscope to illustrate the heat
conversion means. FIG. 27 is a view showing to illustrate a minute
uneven structure having an antireflection effect. FIG. 28 is a
perspective view showing the distal end part of the flexible
endoscope. FIG. 29 is a perspective view of the distal end part of
the rigid endoscope showing an exemplary measure to prevent flare
caused by illumination light. FIG. 30 is a sectional view of the
distal end part of the rigid endoscope of FIG. 29. FIGS. 31 and 32
are each a partial sectional view of the distal end part of the
rigid endoscope showing a modification example of the measure to
prevent flare caused by illumination light.
[0112] Note that, in the description of the present embodiment, for
components same as in the above-mentioned embodiments, the same
symbols are used, and descriptions thereof are omitted.
[0113] As shown in FIG. 20, the rigid endoscope 1 of the present
embodiment is so configured that the cover glass 15 is held by the
distal end portion 2. As shown in FIG. 21, the cover glass 15 has a
shape to essentially cover the distal end surface of the rigid
endoscope 1, and is so disposed that the distal end surface 2a and
the glass surface portion 15a of the distal end portion 2 are
positioned in the same plane.
[0114] On the glass surface portion 15a of the cover glass 15,
there is film-formed a hydrophilic portion 27 of a hydrophilic film
as a defogging coating, continuous with the distal end surface 2a
of the distal end portion 2. Note that the irradiating surface 17a
of the light guide 17 is in contact with a rear surface of the
cover glass 15.
[0115] With the rigid endoscope 1 of the present embodiment thus
configured, the illumination light from the irradiating surface 17a
of the light guide 17 warms a rear surface portion of the cover
glass 15 that is in contact with the irradiating surface 17a. The
heat by the illumination light of the light guide 17 conducts and
spreads over the entirety of the cover glass 15, thus preventing
moisture condensation due to temperature difference between inner
abdominal cavity and the outside.
[0116] As a result, the rigid endoscope 1 of the present embodiment
can achieve the effects of the above-mentioned first embodiment,
i.e., the defogging and hydrophilic effects by the hydrophilic
portion 27, as well as prevent production of water drops in the
light path of the image pickup light from the cover glass 15
through the optical lens group 18 and the relay lens group to be
incident into the image pickup device unit in the camera head 9,
thus obtaining a clearer endoscope image without a photographed
image of the inner abdominal cavity influenced by distortion due to
fogging, water drops, etc.
[0117] Note that, as shown in FIG. 22, the cover glass 15 may
include a protruding portion 35 protruding from a part of the outer
circumference portion of the cover glass 15 and having a surface
portion 35a in the same plane as the glass surface portion 15a. The
protruding portion 35 has here, an essentially arc-shaped outer
circumference, which overlaps a part of the irradiating surface 17a
of the light guide 17 to be heated by transmission of the
illumination light. The protruding portion 35 conducts an amount of
heat from the illumination light to the cover glass 15 to allow
sufficiently preventing moisture condensation.
[0118] In other words, the protruding portion 35 has an area that
is irradiated with an amount of illumination light that allows an
enough heating to prevent moisture condensation on the cover glass
15. As a result, the rigid endoscope 1 can achieve the
above-mentioned effects even if the cover glass 15 is shaped
including the protruding portion 35.
[0119] Note that structures to efficiently convert the illumination
light from the light guide 17 to heat may include one where a part
of the cover glass 15 or the protruding portion 35 overlapped with
the irradiating surface 17a of the light guide 17 may be subjected
to a surface roughening processing to be provided as heat
conversion portions 27, 28, respectively, as shown in FIGS. 23 and
24.
[0120] The heat conversion portions 27, 28 subjected to the surface
roughening processing is subjected to a graining processing such as
of the so-called frosted glass, e.g., thus enabling more
efficiently converting the illumination light from the light guide
17 to heat.
[0121] The above-mentioned part of the cover glass 15 and the
surface of the protruding portion 35, which are subjected to the
surface roughening processing into the heat conversion portions 27,
28, respectively, may be either on a front surface side configuring
a part of the distal end surface of the distal end portion 2, or a
back surface side opposed to the irradiating surface 17a of the
light guide 17, as shown in FIGS. 25 and 26.
[0122] In FIG. 25, if the surface of the heat conversion portions
27, 28 that is subjected to the surface roughening processing is on
the front surface, the illumination light generates heat in the
vicinity of the glass surface portion 15a of the cover glass 15 on
which moisture condensation occurs. Thus, the amount of heat for
preventing moisture condensation can be efficiently conducted to
the glass surface portion 15a of the cover glass 15.
[0123] On the other hand, as shown in FIG. 26, if the surface of
the heat conversion portions 27, 28 subjected to the surface
roughening processing is on the back side, illumination light
before incident into the cover glass 15 causes the heat conversion
portions 27, 28 to generate heat. Thus, it is enabled to reduce
lens flare caused by scattered light of the illumination light
incident into the optical lens group 18 through the cover glass
15.
[0124] Note that, as mentioned above, the heat conversion portions
27, 28 are not to be subjected limitatively to the surface
roughening processing but are sufficed to be configured to
efficiently convert the illumination light to heat and may be
processed to be colored in, e.g., black, gray, purple, etc.
[0125] The heat conversion portions 27, 28, in addition to be
configured to efficiently convert the illumination light to heat,
may further be subjected to a multi-coating, antireflection (AR)
coating, etc., with silicon dioxide (SiO2), magnesium fluoride
(MgF2), etc., for preventing lens flare by the illumination light
as mentioned above. Providing each of these coats can better the
light transmittance and improve light amount of the illumination
light attenuated by the heat conversion.
[0126] Furthermore, to prevent lens flare by the illumination
light, the heat conversion portions 27, 28 may have a surface
having a minute uneven structure with an antireflection effect as
shown in FIG. 27. To describe in detail, the surface having a
minute uneven structure having an antireflection effect refers to a
surface arranged with a countless number of structures of, e.g.,
triangular pyramids each having a size not greater than a light
wavelength, with a length of one side of 10 s nm to 300 nm and a
height of 10 s nm to 500 nm. Note that the minute uneven structures
with antireflection effect are not limited to triangular pyramids
but may be circular cones, quadrangular pyramids, polyhedral cones,
etc.
[0127] The minute uneven structure having an antireflection effect
can restrain reduction of the transmittance of the illumination
light, by means of the uneven structures each sized not greater
than that of a light wavelength.
[0128] The above-described configuration for heat conversion with
the illumination light of the light guide 17 is not to be
limitatively applied to the rigid endoscope 1, but may also be
applied to the flexible endoscope 40 as shown in FIG. 28.
Specifically, there is provided a heat conduction portion 56 that
integrally couples the observation window 51 and, here, the
illumination window 52. The illumination window 52 is subjected to
a surface processing with the above-described graining, coloring
processing, various coatings, or minute uneven structure having an
antireflection effect, and the heat heated by the illumination
light is conducted to the observation window 51 through the heat
conduction portion 56. Thus, the conducted heat prevents moisture
condensation from occurring on the observation window 51.
[0129] In addition, to prevent lens flare, which is caused by
scattered light of the illumination light incident into the optical
lens group 18, the cover glass 15 may be provided inclined at a
predetermined angle .alpha. relative to an optical axes O of the
photographing light, as shown in FIGS. 29 and 30.
[0130] Furthermore, to prevent lens flare, an irradiating surface
17b of the light guide 17 may be diagonally cut to an extent not
exerting an influence on illumination, as shown in FIG. 31. Still
furthermore, there may be provided oblique steps as an irradiating
surface 17c of the light guide 17, as shown in FIG. 32.
[0131] The invention described in each of the above-described
embodiments is not limited to the each embodiment, but various
modifications can be otherwise implemented without departing from
the spirit of the invention in the practical phase. Moreover, each
of the above embodiments includes various phases of inventions, and
various inventions can be extracted by appropriately combining a
plurality of disclosed constituent features.
[0132] For example, if the problem described in the section of
problems to be solved by the invention can be solved and the effect
described in the effect of the invention be acquired even if some
constituent features are deleted from all the constituent features
shown in each embodiment, then the configuration excluding those
constituent features can be extracted as an invention.
* * * * *